<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style lang="css">
    .watermelon {
      width: 100px;
      height: 100px;
      background-color: red;
      border-radius: 50%;
      clip-path: polygon(100% 100%, 0 100%, 50% 0);
      border-bottom: 10px solid green;
    }

    .triangle {
      width: 100px;
      height: 100px;
      background-color: red;
      clip-path: polygon(0 0, 0 100%, 100% 50%);
    }

    .diamond {
      width: 100px;
      height: 80px;
      margin: 20px;
      border-radius: 50%;
      background-image: linear-gradient(#ddf5ff, #29bcf7);
      clip-path: polygon(50% 100%, 100% 10%, 0 10%);
    }

    .demo_box {
      width: 100px;
      height: 100px;
      border-radius: 50%;
      background: #ffa700;
      clip-path: polygon(0% 100%, 100% 100%, 100% 0%, 0% 0%, 0% 25%, 50% 50%, 0% 80%);
      animation: a 1s infinite alternate;
    }

    @keyframes a {

      0%,
      10% {
        clip-path: polygon(0% 100%, 100% 100%, 100% 0%, 0% 0%, 0% 25%, 50% 50%, 0% 80%)
      }

      90%,
      100% {
        clip-path: polygon(0% 100%, 100% 100%, 100% 0%, 0% 0%, 0% 50%, 60% 50%, 0% 60%)
      }
    }
  </style>
</head>

<body>
  <div class="watermelon"></div>
  <div class="triangle"></div>
  <div class="diamond"></div>
  <div class="demo_box"></div>
</body>

</html>